The present invention relates to the specific field of mail processing, and in particular to a dynamic weighing module interposed between a feeder/extractor and a machine for franking mailpieces and provided with a device for guiding these pieces and holding them in position.
Dynamic weighing modules intended to be employed with franking machines are well known. French Application No. 2 388 362 (POSTALIA) illustrates a particular example thereof. Such devices are formed by a weighing platform and drive belts for automatically transporting the mailpieces from one edge of this platform to the other. The weighing module can be used alone, but it is usually inserted in a mail processing assembly between the inlet of the franking module and the outlet of the feeder/extraction module from which the closed envelopes having to be franked are ejected.
In these mail processing assemblies, the transport of the mailpieces during the so-called dynamic weighing step, is particularly important for correct franking. In effect, faulty positioning on the weighing platform may lead, on the one hand, to phenomena of jamming at the inlet of the franking module and, on the other hand, to defective printing of the indicia which are in that case no longer printed perfectly horizontally (a horizontal line will for example be represented in a wavy form).
Now, the consequences of such defective printing are particularly important insofar as, the indicia being a monetary value, the envelope risks being rejected by the Postal Administration.
In order to limit these shortcomings, U.S. Pat. No. 4,856,604 provided holding the mailpieces firmly on the weighing platform by means of presser rollers. Unfortunately, this solution does not suffice in order to avoid all the improper positionings of the mailpieces. Applicants have thus sought to identify the principal causes of such improper positionings in order to find an overall solution to these problems. Unfortunately these causes are multiple and depend on how the envelopes are both filled and closed. In effect, filling of the envelopes by hand is often irregular, for example without the documents being inserted completely to the bottom of the envelope. They are also insufficiently crushed. This results in an imprecise closure of the flaps which disturbs longitudinal wedging along the feed path. These flaps, like the contents of the envelope, may also be bent, as a result of prior preparation of the mail in a bundle by means of an elastic band, which, for thick envelopes, may lead to jamming at the inlet of the franking module. Finally, it is rare for the charge of the mailpieces in the feeder/extraction module to be optimal, i.e. with efficient wedging along the feed path.
It is an object of the present invention to solve these problems simply and economically by providing the weighing module with a holding and guiding device guaranteeing a perfect introduction of the mailpieces in the franking machine. One object of the invention is thus to ensure a precise transfer of the envelopes from the extractor towards the franking machine. Another object is to ensure that the envelopes are held flat.
These objects are achieved by a dynamic weighing module comprising a weighing platform, a vertical, longitudinal registration wall, drive belts for transporting the mailpieces from a position upstream of this platform towards a downstream position, and support means fast with the dynamic weighing module and on which is mounted at least one bearing element intended to hold the mailpieces on the weighing platform dining transport thereof from said upstream position towards said downstream position, characterized in that said support element is inclined towards said registration wall by a determined angle xcex1 so as to guide these mailpieces against said vertical longitudinal registration wall. This determined angle is included between some degrees and 35xc2x0, and preferably equal to about 25xc2x0.
In this way, the mailpieces are transported on the weighing platform with perfect lateral wedging, guaranteeing subsequent printing which is particularly precise.
These support means are preferably constituted by the vertical longitudinal registration wall. They may also be constituted by a plate in the form of a ┌ with a vertical longitudinal wall forming the vertical longitudinal registration wall and a horizontal longitudinal wall forming support for said bearing elements.
According to a first embodiment, the bearing element comprises an elastic holding arm, at the end of which a supple brush is fixed.
According to a second embodiment, this bearing element comprises an elastic holding arm, at the end of which is fixed a supple pressure roller, for example made of foam.
According to a third embodiment, this bearing element comprises an elastic holding arm, at the end of which is fixed a supple pad formed by one or more juxtaposed elementary pads.
In an advantageous variant embodiment, the support means further comprise a cover forming articulated lid for the dynamic weighing module. This lid may constitute a static weighing platform.
The dynamic weighing module may advantageously comprise at the level of said bearing element a drive belt, of which the width is at least equal to that of the brush or the pressure roller.